Diethanolamine (DEA) and triethanolamine (TEA) are widely used in cosmetic products such as creams, skin cleaners, and shampoos. In a 14-day repeated-dose study conducted by the National Toxicology Program, TEA was found to be more toxic to the skin of rats than mice after dermal application. Dermal absorption studies of TEA in F344 rats and B6C3F1 mice were initiated to help explain species differences in sensitivity to this chemical. The interscapular area of male rats and mice were clipped, and screened rings were mounted over the intended site of chemical application. 14C-TEA dissolved in acetone was applied within the tissue caps to rats and mice. Blood samples were taken at eight time points over a 48 hour period after dosing, oxidized to CO2, and assayed for 14C by liquid scintillation counting. Radioactivity in urine, feces, tissue caps and skin sections from the site of application were also counted. TEA was absorbed after dermal application in rats and mice; however, the rate of absorption was greater in mice and the level of chemical retained at the site of application was greater in rats. Similar comparative dermal absorption studies of DEA In rats and mice are planned.